]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference
authorMinchan Kim <minchan@kernel.org>
Thu, 16 Nov 2017 01:33:11 +0000 (17:33 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 16 Nov 2017 02:21:02 +0000 (18:21 -0800)
commitaa8d22a11da933dbf880b4933b58931f4aefe91c
treeed7a7c1ecdfa4da6079858dfc0cfb6fbb65e3286
parent0bcac06f27d7528591c27ac2b093ccd71c5d0168
mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference

When SWP_SYNCHRONOUS_IO swapped-in pages are shared by several
processes, it can cause unnecessary memory wastage by skipping swap
cache.  Because, with swapin fault by read, they could share a page if
the page were in swap cache.  Thus, it avoids allocating same content
new pages.

This patch makes the swapcache skipping work only if the swap pte is
non-sharable.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1507620825-5537-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/swap.h
mm/memory.c
mm/swapfile.c